Millennium Development Goal (MDG) 4 is to reduce child mortality by two thirds between 1990 and 2015. Immunization plays a key part in this, as well as contributing significantly to MDG 5 - improving maternal health and reducing maternal mortality, and MDG 6 - combating HIV/AIDS, malaria and other diseases.

Immunization has saved the lives of millions of children in the three decades since the launch of the Expanded Programme on Immunization (EPI) in 1974. Yet over 27 million children below the age of one and 40 million pregnant women worldwide are still overlooked by routine immunization services (1).

As a result, vaccine-preventable diseases are estimated to cause more than 2 million deaths every year. These include 1.4 million deaths of children under five, and of these, the 395,000 who currently die from measles, the 290,000 who fall to pertussis (whooping cough) and the 257,000 who perish as a result of neonatal tetanus (2).

A further 1.1 million young children die from infections of pneumococcus and rotavirus, for which vaccines will soon be available. It is expected that improvements and cost reductions in the current vaccines will make them available in the near future to all children who need them.

The effectiveness of immunization is thoroughly proven. Unlike most other health and development interventions, immunization does not simply raise the chances that children will resist a disease: it virtually guarantees they will.

Each year since 1990, routine immunization with vaccines against diphtheria, pertussis and tetanus has reached more than 70 per cent of all children, an extraordinary accomplishment considering that more than 130 million children are born each year and need to be immunized. Combined with accelerated disease control programmes, routine services have contributed significantly to child survival, averting more than 2 million deaths a year and preventing countless episodes of illness and disability.

Immunization also provides a network and a mechanism by which health services can make contact with the children and women whom they need to reach with other interventions, such as vitamin A supplementation, the delivery of insecticide-treated bednets to combat malaria, and deworming medicine.

Such an integrated approach is not only the most effective way to protect the health of all children, including the most marginalized. It is also a cost-effective way of building up health systems through which the overall impact of immunization on child survival becomes far greater than the sum of its parts.